Multipole circuit breaker



G. S. HARPER MULTIPOLE CIRCUIT BREAKER May 13, 1969 Sheet Filed Feb. 23, 1967 INVENTOR GEORGE 5. HARPER 5? V pawn V a Q. t

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May 13, 1969 G- s. HARPER MULTIPOLE CIRCUIT BREAKER Filed Feb. 23, 1967 Sheet INVENT OR m m H S. E 6 m w ORNEYS G. S. HARPER MULTIPOLE CIRCUIT BREAKER May 13, 1969 Sheet J 0f5 Filed Feb. 25, '19s? FIG. 10, I

INVENTOR GEORGES. HARPER & 4

United States Patent O U.S. Cl. 335-40 7 6 Claims ABSTRACT OF THE DISCLOSURE A multipole circuit breaker allowing selective manual making and breaking of the poles and automatic simultaneous breaking of the poles under a circuit overload condition by means of a continuous trip bar disposed between the striker of the trip lever and the armature of the electromagnet of each pole.

This invention relates to a circuit breaker having a combination of tripping mechanisms such that any number of single poles or combination of poles may be turned to the on or off position. Regardless of the position of any of the poles or combination thereof, an overload on any one pole will cause all poles in the on position to open simultaneously.

The present state of the are concerning multipole circuit breakers is such that their construction may be divided into three categories. First, there are units having the handles of all poles tied together with a rigid pin. In this case all poles turn on and off together manually. An overload on any pole causes all poles to turn off simultaneous- 1y. Second, there are units in which the handles of a breaker are not tied together with rigid pin but are connected with a mechanism such that all poles must be turned on together manually. Turning one pole off manually turns off all other poles simultaneously, and an overload on any one pole causes all poles to turn off simultaneously. Third, there are units having the handles of a breaker not tied together with a rigid pin but built with a mechanism such that any combination of poles can be turned on together manually or any combination of poles can be turned off together manually. However, an overload on any single pole or combination of poles does not turn the other poles off.

It is, therefore, an object of the present invention to produce a multipole circuit breaker which is more versatile than those types in existence at the present time.

It is also an object of the present invention to provide a multipole circuit breaker which may be economically and readily produced.

By using the construction, described in the following specification, any combination of handles of a multipole breaker can be joined together by rigid pins, and regardless of the position of the poles either on or off, an overload on any one pole will open all on poles. Any combinations of poles can be turned on or off manually without affecting the position of the other poles.

The principles of the present invention, however, both as to structure and operation, together with additional objects and advantages thereof, which will be apparent to those skilled in the art, will best be understood from the following detailed description when read in conjunction with the accompanying drawings in which:

FIG. 1 is a three pole circuit breaker showing the handles of two poles tied together with a rigid pin and the handle of the third pole free to operate independently from the other two poles;

3,444,488 Patented May 13, 1969 ICC FIG. 2 is an elevation view, with some parts in section, of a unit with one portion of the housing removed to show the main elements of unit in the on" position with the contacts closed;

FIG. 3 is a view similar to FIG. 2 showing the mechanism in the intermediate tripping position with the contacts open;

FIG. 4 is a view similar to FIGS. 2 and 3 showing the mechanism and contacts in the open or off position;

FIG. 5 is a detail view of the sear pin and striker bar assembly;

FIG. 6 is an enlarged detail view of the sear pin and striker bar assembly and its relation to the cam in the untripped position;

FIG. 7 is an enlarged detail view of the trip lever;

FIG. 8 is an enlarged detail view of the armature;

FIG. 9 is an enlarged detail view of the trip bar;

FIG. 10 is a section view taken along line 10-10 of FIG. 4; and

FIG. 11 is a section view taken along line 1111 of FIG. 4.

Referring now to the figures and in particular to FIGS. 2 to 4, a frame 11 is supported in the housing 10, the latter being formed of a molded plastic of good electrical insulation properties. Mounted on the frame 11 are the operating elements of the circuit breaker which move the movable contact 12 into and out of engagement with the fixed contact 13. Portions of the frame 11 have been omitted from FIGS. 3 and 4 for the sake of clarity. The entire frame 11 is shown in FIG. 2.

The movable contact 12 is secured to a lever 14 which is pivotally and slidably mounted on the frame by a pin 15 and an elongated opening 16. Pin 15 is mounted in the frame 11 intermediate the ends while the ends extend beyond the frame and fit snugly into recesses 17 molded in the housing portions 10 and 10' as seen in FIG. 11. A spring 18 is wound around the pin 15 and is provided with a biasing arm 19 bearing against the lever 14 and a reaction arm 20 hearing against the frame 11.

An actuating lever 21 is pivotally mounted on the frame 11 by a pin 22. A spring 23 is wound around the pin 22 and has a biasing arm 24 bearing against a pin 25 and a reaction arm 26 hearing against the frame 11.

A pair of spaced parallel L-shaped links 27 are pivotally mounted on pin 25 and are pivotally connected to a spaced pair of links 28 by a pin 29. The links 28 are pivotally connected by a pin 30 to straddle the lever 14.

A sear pin 31 is rotatably supported in link 27 at the bend of the L and, between the links, is provided With a reduced section in the form of a fiat surface 32 (see FIG. 5) Which acts as a scar for edge 42 of cam 40 (see FIG. 6). An arm or striker bar 33 is mounted rigidly and nonrotatably on the sear pin 31 and carries a tab 34 bent up from one end of the arm. The end of the sear pin 31 is square to accommodate the square hole in arm 33. After assembly, the end of sear pin 31 is peened tight against arm 33 thus permanently keying the shaft and arm together. A spring 35 is wound around sear pin 31 and is provided with arms 36 and 37 hearing respectively against a stop 38 integral with one arm of link 27 and against an extension 39 of arm 33. The spring is wound to urge the extension against the stop 38.

A cam 40 is pivotally mounted on pin 25 between the parallel arms of link 27. One leg 41 of the cam (see FIG. 6) is provided with an edge portion 42 for engagement with the flat portion 32 of sear pin 31, and the other leg 43 of the cam is provided with a curved section 44 for engagement with a pin 45 carried by links 28. A lock ing recess 46 is located between the legs at the end of cam section 44.

The frame 11 is provided with a shelf 47 on which is mounted an electromagnet 48. The latter has a winding, one end of which is connected in series electrically with terminal 49 and the other end in series electrically with a braided, flexible copper wire 50 secured to lever 14, movable contact 12, fixed contact 13, contact support 51 and terminal 52. An armature 53 is pivotally mounted on the frame by a pin 54 and is secured to an armature lever 55 to form therewith a bell crank 56. Spring 57 is mounted on pin 54 to bias the bell crank towards the position shown in FIG. 2. The free end of the armature lever 55 forms an arcuate trigger cam surface 58. A trip lever 70, shown in detail in FIG. 7, is mounted on pin 75 and is biased clockwise (FIG. 2) by spring 76 having the fixed .end 78 resting on frame 11 and the biasing end 77 located against trip lever 70. Trip bar 67, shown in detail in FIG. 9, has tabs 68 so located on shaft 69 that they are between armature 53 and striker 71 of trip lever 70. In the closed contact position, the linkage is in the position shown in FIG. 2 with the tab portion 34 of the sear pin 31 adjacent the arcuate trigger cam surface 58 at the end of armature lever 55.

On overload, the electromagnet 48 is energized to attract armature 53 to pivot armature lever 55 bringing the trigger cam surface 58 into contact with tab 34 to rotate striker bar 33 and sear pin 31. Rotation of the sear pin 31 presents the reduced section 32 to the edge 42 of the cam 40, allowing the cam 40 to rotate counterclockwise about pin 25 to release pin 45 from recess 46, as illustrated in FIG. 3. The release of pin 45 allows the linkage to collapse and the lever 14 to pivot about pin 15 to separate the contacts 12 and 13. The are drawn by the separating contacts is extinguished by its reaction to the arc chutes 59 and 60 in the usual manner. Vent opening 74 is provided in the casing closely adjacent the arc chutes and serves as a pressure release for the gases produced by arcing. At the same time the cam 40 rotates counterclockwise from the position shown in FIG. 2 to the position shown in FIG. 3. Pin 29, connecting links 27 and 28, also rotates counterclockwise. In doing so it strikes the follower 72 of trip lever 70 causing it to rotate counterclockwise about pin 75. Thereupon the striker 71 of trip lever 70 hits the tab 68 of trip bar 67 causing the entire bar with all its tabs to rotate clockwise. These tabs in turn strike the armatures 53 of all poles of the unit thereby causing all mechanisms to trip and open contacts 12 and 13 of all poles. The force of spring 23 reacts against pin 25 to rotate the lever 21 to the position shown in FIG. 4. The movement of pin 25 about pin 22, under the urging of spring 23, realigns links 27 and 28 and cam element 40 to replace pin 45 in recess 46 as shown in FIG. 4. In order to close the contacts, the handle is rotated clockwise about pin 22 to force the linkage down to rotate lever 14. When the contacts close, they become a pivot about which lever 14 is rotated against the force of spring 18 to load the spring and linkage for future toggle action. The trip bar 67 is rotated counterclockwise back to its original position by the pressure of the armatures 53 against the tabs 68. The trip lever 70 is rotated clockwise back to its original position by spring 76.

The housing is formed by two mirror-image sections 10 and 10' (FIGS. 1 and 11) which are secured together by rivets 62 passing through openings 61 in the housing.

Each housing section (see FIG. 2) is provided with recesses 63 molded in the meeting faces. The recesses 63 are provided with enlarged hexagonal portions 64. When the sections are secured together the recesses 63 combine to provide openings which receive threaded metal ferrules 65 with hexagonal heads by which the assembly is secured to a support. The recesses 66 combine to provide openings for the reception of the threaded terminals 49 and 52.

The present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore to be embraced therein.

What is claimed is:

1. A multipole circuit breaker comprising at least two circuit breaker units, each unit comprising a pair of contacts, a handle coupled to each unit for moving at least one of said contacts to manually open and close said contacts, a current responsive device in each unit including a trip armature and collapsible toggle coupled to said movable contact for opening said contacts when the current to said device exceeds a predetermined value, means coupled to each of said current responsive devices for automatically resetting said toggle after operation of said current responsive devices, a common trip bar interconnecting each of said current responsive devices where actuation of said trip bar actuates said armatures and causes all closed contacts to be opened, and an independent trip lever between each toggle and said common trip bar.

2. Apparatus according to claim 1 wherein said current responsive devices each comprise an electromagnet and cooperating movable trip armature.

3. A multipole circuit breaker comprising at least two circuit breaker units, each unit comprising a pair of contacts, a handle coupled to each unit for moving at least one of said contacts to manually open and close said contacts, said handle being coupled to said movable contact through a collapsible toggle, an electromagnet in each unit, a movable armature adjacent said electromagnet and coupled to said toggle for collapsing said toggle upon movement of said armature, means coupled to said toggle for automatically resetting it after it has been collapsed, a common trip bar interconnecting said units and including means for collapsing the toggles in all of the units in which the contacts are closed, and an independent trip lever adjacent each toggle for actuating said trip bar when the toggle is collapsed,

4. Apparatus according to claim 3 wherein said trip bar is positioned between the trip lever and armature of each unit, collapse of one of said toggles causing said bar to move the armautre of all other units in which the contacts are closed.

5. A multipole circuit breaker comprising at least two circuit breaker units each of which comprises a frame, a first lever pivotally and slidably mounted on said frame, a second lever pivotally mounted on said frame, a pair of links pivotally connected to each other and to said first and second levers respectively, means for locking said pair of links against pivotal movement with respect to each other, means for unlocking said locking means to permit pivotal movement of said pair of links with respect to each other, said locking means comprising a forked cam member pivotally carried by the second lever, a pin carried by one of said pair of links for reception in the forked cam member, and means holding the forked cam member against pivotal movement comprising a sear rotatably mounted on the other of said pair of links, said sear having a reduced section, means for maintaining the sear against rotation with the reduced section out of contact with the forked cam member, and means urging said forked cam member into contact with the sear, trip means for rotating the sear to present the reduced portion of the sear to the forked cam member, said trip means comprising a bell-crank lever, an electromagnet mounted on the frame adjacent one arm of the bell-crank for attracting said arm upon a predetermined current condition, an abutment carried by the sear in the path of movement of the other arm of the crank for actuation thereby, a trip lever responsive to the unlocking of said pair of links, and a trip bar interconnecting each of said units and being disposed between said bell crank lever and said trip lever, tripping of any single unit causing said trip bar to rotate and strike the bell crank lever of all units thus causing substantially simultaneous tripping of all units.

6. A multipole circuit breaker according to claim 5 wherein said trip bar comprises a rod of sufficient length to traverse the entire multipole circuit breaker, a plurality of tab portions extending from said rod, said tab portions being equal in number to the number of units in said multipole circuit breaker.

References Cited UNITED STATES PATENTS Dyer.

Sprague 3'359 Brackett 3359 Taylor 200116 Kingdon 200116 BERNARD A. GILHEANY, Primary Examiner. 10 H. BROOME, Assistant Examiner. 

